Portable computers have recently become more powerful while at the same time becoming lighter and smaller. Peripheral devices are often used in conjunction with the portable computer to provide increased functionality, such as communications ability or enhanced data storage. One example of a peripheral device is a modem, which allows a user of a portable computer to communicate with other computers using telephone lines. Reduction in the size of peripheral devices has accompanied reductions in the size of portable computers.
Some portable computer systems and peripheral devices, modems in particular, have been designed recently such that the peripheral device is contained on a thin form factor computer card which plugs into a socket recessed within the body of the computer. Such peripheral devices can be carried along with the portable computer and inserted when needed.
Historically, each of the peripheral devices (e.g. modems, memory devices, facsimile, LANs, etc.) has required its own interface circuitry for connecting to the internal circuitry of a portable computer. This interface circuitry required a separate socket for each device, and thus more space in the portable computer. For example, a modem card and a memory card each required a separate socket, and thus two sockets were necessary even though only one was in use at a given time.
Recently, devices have been devised which allow some of these various forms of computer components to be plugged into the same socket of the computer, thereby reducing space required within the portable computer. For example, an international standard which defines the physical and electrical interface specifications for the interchangeability of memory and input/output cards was introduced by the Personal Computer Memory Card International Association (PCMCIA) jointly with the Japanese Electrical Industry Association (JEIDA) in September of 1991. In addition, a specification referred to as an Exchangeable Card Architecture (ExCA) specification, dated Dec. 20, 1991, has been issued by Intel Corporation of Santa Clara, Calif. The ExCA document describes specifications which manufacturers may use to provide interfaces which are ensured of allowing the memory and input/output cards for portable personal computers of different manufacturers to be interchanged.
A socket designed to these specifications allows cards, such as modem and flash memories, to be inserted, used, and removed interchangeably in the same socket. The computer systems used typically contained at least one socket recessed within the computer, such that the inserted computer card containing the modem, flash memory, etc., is protected by the body of the computer surrounding the socket in which the components are coupled.
The PCMCIA specification provides that the personal computer cards have a 68-pin connector located at the end of the card for transmitting signals between the computer and the card. Many system manufacturers desire to connect to critical signals on the integrated circuit card which are not available through the 68-pin connector. One example of such a need is found when the computer card is a modem card, in which case tip-ring connections between an external RJ11 jack and the modem card are needed. Such connections have typically been achieved through a second connector located along the rear edge of the computer card, i.e. the edge which faces to the outside of the computer which the card is inserted. This rear edge is opposite the 68-pin standard interface.
Another method of transferring external signals to a computer card, which can replace or be additive to the rear connectors, is described in a co-pending application, Ser. No. 08/009,135, "Method and Apparatus for Propagating Signals on Integrated Circuit Cards", applicant David C. Scheer, filed Jan. 26, 1993, and assigned to the assignee of the present invention. The "sideswipe" invention disclosed in the above pending application can provide tip-ring connections to a modem card, for example, through embedded contacts in the side of the computer card receptacle. One advantage of such a configuration is, for example, the elimination of the need to directly attach an external connector to the rear of the inserted modem card.
A problem which exists in the side-contacting scheme is the need for flexible interconnectability of computer cards and external connector types with the computer card receptacles built into the body of the computer. For example, a given computer card receptacle may be hardwired for a given type of external communications connector, e.g. where a computer card receptacle designed for use with one-line modem side-contacting cards contains two side contacts which are hardwired to an RJ11 jack in the computer chassis. In such a circumstance the alternative uses of this computer card receptacle are limited. If, for example, a two-line modem card were needed, necessitating a two-line RJ45 external connection, the given computer card receptacle in the above example would not be sufficient, and an alternative or separate computer card receptacle/external connector configuration would be required. Even with the addition of a second computer card receptacle/external connector, however, the types of external connections possible would be limited to the RJ11 and RJ45 types. If, for example, a side-contact computer card were used which was a sound card requiring a stereo audio miniplug interface, the existing RJ11 and RJ45 configurations would not suffice.
Thus, there exists a need for flexibility and interchangeability in the implementation of portable computer systems containing one or more receptacles for use with side-contact computer cards. The addition of extra receptacles and hardwired external connections is not a flexible, generalized solution to the situation where different types of side contact cards, necessitating different types of external communications connections, are desired for use in a portable computer system.